October 11, 2018

The United Nations confronts a future with “the slimmest of
opportunities remaining to avoid unthinkable damage.”

Limiting global warming to 1.5°C will require extreme
changes, including markedly increasing the percentage of electricity from
renewables by mid-century, according to a Sunday report from the
United Nations’ Intergovernmental Panel on Climate Change (IPCC).

The report, commissioned as part of the 2015 Paris climate
agreement, presents a stark portrait of the future unless the world undertakes
“rapid, fair-reaching and unprecedented changes in all aspects of society” in
the next decade or so — changes that thus far have been difficult for
decision-makers to agree on.

“The report shows that we only have the slimmest of
opportunities remaining to avoid unthinkable damage to the climate system that
supports life as we know it,” said Amjad Abdulla, an IPCC board member and
chief negotiator for the Alliance of Small Island States.

Citing over 6,000 scientific reports and using contributions
of 91 authors, the report’s pathways to limit warming vary. But all include
increased levels of clean energy. Most show drastic reductions in coal and oil.

The report includes a wide array of possible scenarios that
would draw down emissions and keep warming below 1.5°C, including bumping the
share of renewables in electricity to 97 percent in the most aggressive
forecast. In a sampling of three scenarios the IPCC selected to show a wide
range of possible climate mitigation approaches, renewables range from a 63 to
77 percent share of electricity by mid-century. The IPCC also included one
scenario that would overshoot the 1.5°C target.

The middle range of the IPCC’s scenarios, where there is
little to no overshoot, require that renewables make up 70 to 85 percent of
electricity by 2050.

Within the same middle range of scenarios, primary energy
from coal drops to 1 to 7 percent, and oil declines to 32 to 74 percent between
2020 and 2050. Use of natural gas would have to drop to between 13 and 60
percent over the same time period, but some scenarios increase gas in
combination with carbon capture and sequestration (CCS). Authors pair coal with
CCS as well, but note that its use hinges on technological advancements and
incentives for deployment at a large scale.

Most 1.5°C pathways include an increased role for nuclear
power, in one case up to 501 percent above 2010 levels by 2050. But in certain
circumstances, nuclear power decreases.

The report also touches on the potential of clean energy
technologies such as energy storage to ease the transition, though the authors
note that “the feasibility of battery storage is challenged by concerns over
the availability of resources and the environmental impacts of its production.”

Ravi Manghani, director of energy storage at Wood Mackenzie
Power & Renewables, said the significant transition presented in the report
will stretch the current bounds of storage technology.

“The level of carbon-free generation needed to meet the
1.5°C pathway will need more than lithium-ion batteries, even if resource constraints
can be resolved,” said Manghani. “The electricity system would require awfully
large amounts of long-duration storage, and a shift toward pumped hydro, or
chemical storage solutions like natural gas, synthetic from renewables with
CCS, hydrogen and others.”

The report elicited dramatic response, with leaders such as
Andrew Steer, president and CEO at World Resources Institute, calling it “a
wakeup call for slumbering world leaders.” Former Chilean president Ricardo
Lagos said it details a threat that "cannot be understated."

And though the comprehensive report presents a jarring
portrait of the future, many of its general takeaways — including the
disproportionate impact of climate change on marginalized groups and the need
to drastically reduce emissions — have been accepted for years.

Global leaders and climate activists have held up the dire
consequences of climate change for decades, with many businesses more
recently joining
the refrain. Still, action so far has been haltingly slow.

“This report is not a wakeup call,” said former Norwegian
Prime Minister Gro Harlem Brundtland. “It is a ticking time bomb. Climate
activists have been calling for decades for leaders to show responsibility and
take urgent action, but we have barely scratched the surface of what needs to
be done.”

According to the International
Energy Agency, renewables accounted for just 23 percent of electricity in
2015. Increasing clean energy adoption at the rate the report calls for will
require $2.4 trillion in investment every year. Bloomberg New Energy
Finance logged clean energy investments at just $138.2 billion
for the first half of 2018.

While businesses, sub-national governments and many
countries have committed to climate action, and achieved some progress — see
the $9 trillion We’re Still In Campaign — slow movement from those that profit
off fossil fuels and staunch resistance from parties like the Trump
administration have made collective action difficult.

Days ahead of the IPCC release, for instance, the
conservative, climate-change-denying Heartland Institute circulated a
pro-fossil-fuel report from the Nongovernmental International Panel on Climate
Change (a group whose scientific rigor has long been questioned) that contends that “the global war on fossil
fuels...was never founded on sound science or economics.”

It’s unclear whether the dramatic conclusions of the IPCC’s
fact-based report can overcome climate denial and galvanize the type of change
it calls for. Global leaders will gather in Poland in December for the next
round of climate talks. According to the IPCC, “the next few years are probably
the most important in our history.”